EVIDENCE is mounting that parents who smoke should quit or stop smoking at home.
Children who breathe secondhand smoke are more likely to struggle with mental health problems, a new study has warned.
The findings, published in the Archives of Pediatrics and Adolescent Medicine add urgency for parents to quit.
But it remains unclear whether tobacco fumes actually take a toll on children's brains or if something else is involved, said researchers led by Mark Hamer of University College London.
"We know that exposure to secondhand smoke is associated with a lot of physical health problems in children, although the mental health side has not been explored," said Hamer.
Exposed
In the US, two of every three children between ages three and 11 are exposed to secondhand smoke.
One in five children aged nine to 17 have been diagnosed with some kind of mental or addictive disorder.
Hamer and his colleagues studied 901 non-smoking British children from ages four to eight, measuring levels of a byproduct of cigarette fumes in the children's saliva.
The more secondhand smoke a child took in, the poorer their mental health.
Compared to the 101 children who breathed in the least smoke, the 361 with the most exposure showed the highest level of mental problems.
But Michael Weitzman, at New York University Medical Center, said the results strengthened evidence that secondhand smoke caused mental health problems in children.
hnews@herald.ie